1. Field of the Invention
Embodiments of the invention include absorbent products having improved dryness. Specifically, the invention pertains to absorbent products having a dryness index within the range between of from about 0 to about 50 gm/180 min.
2. Description of Related Art
Absorbent products, such as baby diapers have a 90 to 95% market penetration in the United States and Europe. The levels of market penetration in some of the emerging market countries such as China and India, however, is less than 5%. Part of the reason for this low level of penetration is the relative high cost of these products in those markets.
Manufacturers of absorbent products in the emerging market countries face an enormous challenge in trying to find ways to produce low cost effective products. The cost of raw materials comprise up to seventy to eighty percent of the cost to manufacture such products. Production of functional absorbent products usually requires a minimum amount of conventional materials, including absorbent components, and leakage-resistant materials. Reducing the amount of material used beyond these minimums can greatly diminish the product's functionality.
Absorbent products such as baby diapers, feminine hygiene pads and adult incontinent products typically are made of several different types of materials. These products usually include a permeable non-woven top sheet, an impermeable back sheet and an absorbent core positioned between the top sheet and the back sheet. The absorbent core typically consists of wood fluff and a water-absorbing polymer, which most commonly is prepared from monomers of acrylic acid. This water-absorbing polymer, referred to as super absorbent polymer (SAP), can constitute anywhere from about 20% up to 50% of the material cost of the product. In addition, availability of SAP fluctuates, and in those times in which there is a shortage of SAP, the costs can be much higher. Wood-based fluff can account for an additional 10-20% of the material cost of the product.
Conventional absorbent garments having wood-based fluff cores tend to release moisture under pressure over the long term. Baby diapers in particular and some adult incontinent diapers may be worn for long periods of time (2 to 8 hours). Wood-based fluff over that period of time can release moisture through pressure or evaporation. Wood-based fluff does not actually absorb the liquid like SAP. The long term comfort of the wearer therefore is compromised due to the release of this moisture.
Accordingly, there is a need in the art for a cost effective absorbent garment having improved long term dryness profile that will provide for a much more comfortable and hygienic product.
The description herein of certain advantages and disadvantages of known elements of absorbent garments, methods, and systems is not intended to limit the scope of the present invention to either their inclusion or exclusion. Indeed, certain embodiments may include one or more known elements without suffering from the disadvantages described herein.